Development of a framework to provide cementing mixtures to mitigate ASR induced deterioration

The demand for aggregates and cement for construction has been rising faster than natural sources can sustain, enhancing the probability of using inferior raw materials that will cause premature deterioration of concrete infrastructures (e.g., alkali-silica reaction, ASR). Therefore, finding new protocols that allow reactive aggregates and new materials in concrete without reducing durability is imperative. This study aims to develop a new mix-design approach based on the chemical composition of the binder toward mitigating ASR. This work tested several blended cement types containing controlled amounts of CaO, SiO₂, and Al₂O₃ for their mechanical properties and resistance to ASR-induced expansion. In addition, experimental investigations were compared with thermodynamic modelling to gain insights into the differences in the deterioration mechanisms. The expansion results of mortar bars combined with the information from thermodynamic modelling suggest that increasing Al₂O₃ and SiO₂ content in the blended mixtures lessens the concentration of alkalis, Ca²⁺ and OH^- in the pore solution of the hydrated mortars, thereby lower ASR-induced expansion development. Moreover, an increase in the amount of C-S-H and C-A-S-H phases is expected, enhancing further binding of alkalis. The results may help select the best options for the mix design to apply in concrete structures where ASR could be expected.